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/*
* Copyright (c) 2021, Arm Limited and Contributors. All rights reserved.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
#include <assert.h>
#include <errno.h>
#include <stdint.h>
#include <string.h>
#include <common/debug.h>
#include <common/uuid.h>
/* Return the hex nibble value of a char */
static int8_t hex_val(char hex)
{
int8_t val = 0;
if ((hex >= '0') && (hex <= '9')) {
val = (int8_t)(hex - '0');
} else if ((hex >= 'a') && (hex <= 'f')) {
val = (int8_t)(hex - 'a' + 0xa);
} else if ((hex >= 'A') && (hex <= 'F')) {
val = (int8_t)(hex - 'A' + 0xa);
} else {
val = -1;
}
return val;
}
/*
* Read hex_src_len hex characters from hex_src, convert to bytes and
* store in buffer pointed to by dest
*/
static int read_hex(uint8_t *dest, char *hex_src, unsigned int hex_src_len)
{
int8_t nibble;
uint8_t byte;
/*
* The string length must be a multiple of 2 to represent an
* exact number of bytes.
*/
assert((hex_src_len % 2U) == 0U);
for (unsigned int i = 0U; i < (hex_src_len / 2U); i++) {
nibble = 0;
byte = 0U;
nibble = hex_val(hex_src[2U * i]);
if (nibble < 0) {
return -1;
}
byte = (uint8_t)nibble;
byte <<= 4U;
nibble = hex_val(hex_src[(2U * i) + 1U]);
if (nibble < 0) {
return -1;
}
byte |= (uint8_t)nibble;
*dest = byte;
dest++;
}
return 0;
}
/* Parse UUIDs of the form aabbccdd-eeff-4099-8877-665544332211 */
int read_uuid(uint8_t *dest, char *uuid)
{
int err;
uint8_t *dest_start = dest;
/* Check that we have enough characters */
if (strnlen(uuid, UUID_STRING_LENGTH) != UUID_STRING_LENGTH) {
WARN("UUID string is too short\n");
return -EINVAL;
}
/* aabbccdd */
err = read_hex(dest, uuid, 8);
uuid += 8;
dest += 4;
/* Check for '-' */
err |= ((*uuid == '-') ? 0 : -1);
uuid++;
/* eeff */
err |= read_hex(dest, uuid, 4);
uuid += 4;
dest += 2;
/* Check for '-' */
err |= ((*uuid == '-') ? 0 : -1);
uuid++;
/* 4099 */
err |= read_hex(dest, uuid, 4);
uuid += 4;
dest += 2;
/* Check for '-' */
err |= ((*uuid == '-') ? 0 : -1);
uuid++;
/* 8877 */
err |= read_hex(dest, uuid, 4);
uuid += 4;
dest += 2;
/* Check for '-' */
err |= ((*uuid == '-') ? 0 : -1);
uuid++;
/* 665544332211 */
err |= read_hex(dest, uuid, 12);
uuid += 12;
dest += 6;
if (err < 0) {
WARN("Error parsing UUID\n");
/* Clear the buffer on error */
memset((void *)dest_start, '\0', UUID_BYTES_LENGTH * sizeof(uint8_t));
return -EINVAL;
}
return 0;
}